URLEncode URLDecode
 

<SCRIPT LANGUAGE="JavaScript" TYPE="text/javascript">
// ====================================================================
//       URLEncode and URLDecode functions
//
// Copyright Albion Research Ltd. 2002
// http://www.albionresearch.com/
//
// You may copy these functions providing that 
// (a) you leave this copyright notice intact, and 
// (b) if you use these functions on a publicly accessible
//     web site you include a credit somewhere on the web site 
//     with a link back to http://www.albionresarch.com/
//
// If you find or fix any bugs, please let us know at albionresearch.com
//
// SpecialThanks to Neelesh Thakur for being the first to
// report a bug in URLDecode() - now fixed 2003-02-19.
// ====================================================================
function URLEncode( )
{
 // The Javascript escape and unescape functions do not correspond
 // with what browsers actually do...
 var SAFECHARS = "0123456789" +     // Numeric
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + // Alphabetic
     "abcdefghijklmnopqrstuvwxyz" +
     "-_.!~*'()";     // RFC2396 Mark characters
 var HEX = "0123456789ABCDEF";

 var plaintext = document.URLForm.F1.value;
 var encoded = "";
 for (var i = 0; i < plaintext.length; i++ ) {
  var ch = plaintext.charAt(i);
     if (ch == " ") {
      encoded += "+";    // x-www-urlencoded, rather than %20
  } else if (SAFECHARS.indexOf(ch) != -1) {
      encoded += ch;
  } else {
      var charCode = ch.charCodeAt(0);
   if (charCode > 255) {
       alert( "Unicode Character '" 
                        + ch 
                        + "' cannot be encoded using standard URL encoding.\n" +
              "(URL encoding only supports 8-bit characters.)\n" +
        "A space (+) will be substituted." );
    encoded += "+";
   } else {
    encoded += "%";
    encoded += HEX.charAt((charCode >> 4) & 0xF);
    encoded += HEX.charAt(charCode & 0xF);
   }
  }
 } // for

 document.URLForm.F2.value = encoded;
 return false;
};

function URLDecode( )
{
   // Replace + with ' '
   // Replace %xx with equivalent character
   // Put [ERROR] in output if %xx is invalid.
   var HEXCHARS = "0123456789ABCDEFabcdef"; 
   var encoded = document.URLForm.F2.value;
   var plaintext = "";
   var i = 0;
   while (i < encoded.length) {
       var ch = encoded.charAt(i);
    if (ch == "+") {
        plaintext += " ";
     i++;
    } else if (ch == "%") {
   if (i < (encoded.length-2) 
     && HEXCHARS.indexOf(encoded.charAt(i+1)) != -1 
     && HEXCHARS.indexOf(encoded.charAt(i+2)) != -1 ) {
    plaintext += unescape( encoded.substr(i,3) );
    i += 3;
   } else {
    alert( 'Bad escape combination near ...' + encoded.substr(i) );
    plaintext += "%[ERROR]";
    i++;
   }
  } else {
     plaintext += ch;
     i++;
  }
 } // while
   document.URLForm.F1.value = plaintext;
   return false;
};
</SCRIPT>

사용법 : 
    var sStr = "ddcc!@!#";
    alert(sStr.URLEncode());
    alert(sStr.URLEncode().URLDecode());


또다른 방법

<SCRIPT LANGUAGE="JavaScript" TYPE="text/javascript">
function encodeURL(str){
    var str = str;
     str = "".concat(str);
     
    var s0, i, s, u;
    s0 = "";                // encoded str
    for (i = 0; i < str.length; i++){   // scan the source
        s = str.charAt(i);
        u = str.charCodeAt(i);          // get unicode of the char
        if (s == " "){s0 += "+";}       // SP should be converted to "+"
        else {
            if ( u == 0x2a || u == 0x2d || u == 0x2e || u == 0x5f || ((u >= 0x30) && (u <= 0x39)) || ((u >= 0x41) && (u <= 0x5a)) || ((u >= 0x61) && (u <= 0x7a))){       // check for escape
                s0 = s0 + s;            // don't escape
            }
            else {                  // escape
                if ((u >= 0x0) && (u <= 0x7f)){     // single byte format
                    s = "0"+u.toString(16);
                    s0 += "%"+ s.substr(s.length-2);
                }
                else if (u > 0x1fffff){     // quaternary byte format (extended)
                    s0 += "%" + (oxf0 + ((u & 0x1c0000) >> 18)).toString(16);
                    s0 += "%" + (0x80 + ((u & 0x3f000) >> 12)).toString(16);
                    s0 += "%" + (0x80 + ((u & 0xfc0) >> 6)).toString(16);
                    s0 += "%" + (0x80 + (u & 0x3f)).toString(16);
                }
                else if (u > 0x7ff){        // triple byte format
                    s0 += "%" + (0xe0 + ((u & 0xf000) >> 12)).toString(16);
                    s0 += "%" + (0x80 + ((u & 0xfc0) >> 6)).toString(16);
                    s0 += "%" + (0x80 + (u & 0x3f)).toString(16);
                }
                else {                      // double byte format
                    s0 += "%" + (0xc0 + ((u & 0x7c0) >> 6)).toString(16);
                    s0 += "%" + (0x80 + (u & 0x3f)).toString(16);
                }
            }
        }
    }
    return s0;

}
 

/*  Function Equivalent to java.net.URLDecoder.decode(String, "UTF-8")
    Copyright (C) 2002, Cresc Corp.
    Version: 1.0

*/

function decodeURL(str){
    var s0, i, j, s, ss, u, n, f;
    s0 = "";                // decoded str
    for (i = 0; i < str.length; i++){   // scan the source str
        s = str.charAt(i);
        if (s == "+"){s0 += " ";}       // "+" should be changed to SP
        else {
            if (s != "%"){s0 += s;}     // add an unescaped char
            else{               // escape sequence decoding
                u = 0;          // unicode of the character
                f = 1;          // escape flag, zero means end of this sequence
                while (true) {
                    ss = "";        // local str to parse as int
                        for (j = 0; j < 2; j++ ) {  // get two maximum hex characters for parse
                            sss = str.charAt(++i);
                            if (((sss >= "0") && (sss <= "9")) || ((sss >= "a") && (sss <= "f"))  || ((sss >= "A") && (sss <= "F"))) {
                                ss += sss;      // if hex, add the hex character
                            } else {--i; break;}    // not a hex char., exit the loop
                        }
                    n = parseInt(ss, 16);           // parse the hex str as byte
                    if (n <= 0x7f){u = n; f = 1;}   // single byte format
                    if ((n >= 0xc0) && (n <= 0xdf)){u = n & 0x1f; f = 2;}   // double byte format
                    if ((n >= 0xe0) && (n <= 0xef)){u = n & 0x0f; f = 3;}   // triple byte format
                    if ((n >= 0xf0) && (n <= 0xf7)){u = n & 0x07; f = 4;}   // quaternary byte format (extended)
                    if ((n >= 0x80) && (n <= 0xbf)){u = (u << 6) + (n & 0x3f); --f;}         // not a first, shift and add 6 lower bits
                    if (f <= 1){break;}         // end of the utf byte sequence
                    if (str.charAt(i + 1) == "%"){ i++ ;}                   // test for the next shift byte
                    else {break;}                   // abnormal, format error
                }
            s0 += String.fromCharCode(u);           // add the escaped character
            }
        }
    }
    return s0;

}
</SCRIPT>